1. Field of the Invention:
The present invention relates to block copolymers useful as pigment dispersants.
2. Description of the Related Art:
Pigment dispersants have been used to improve the properties of inks. In general, dispersants promote the dispersion of the pigment in the ink and stabilize the dispersion. Lecithin is an example of such a dispersant.
U.S. Pat. No. 4,704,165 to Nakamura et al discloses an example of another dispersant. This patent discloses a phosphate ester pigment dispersant for organic, inorganic and extender pigments in compositions wherein the pigment is present in high concentrations as a coloring agent (printing inks, paints, coating agents and synthetic resins) and compositions useful as a paint.
U.S. Pat. No. 4,350,535 to Ishijima et al also discloses a phosphate ester dispersant that improves the long-term storage stability of aqueous coating compositions and adhesives containing a metallic powder pigment.